The aim of this study provides a theoretical basis to spots event organizers and proposes some pertinent recommendations on various risks of sports events. Sports events have a series of uncertain factors and various risks which certainly will bring many adverse impacts on sports events. The study makes an in-depth risk assessment on sports events through grey system theory, makes an analysis directing at various factors influencing sports event risks and makes a quantitative assessment to risks using a grey comprehensive assessment method combining a grading system. This research indicates that in sports event risks, the property risk, personal risk, liability risk, management risk and financial risk have some restrictions on sports events, especially the financial risk.